BLT add-on 100 pts minimum ( believe VGC is same but not 100% on this ).
Note that yesterday members here are posting that if you bought BLT before 2010
point chart was released that you may still for a limited time buy an add-on at BLT as low as 25 points but it seems that 100 pts will still be minimum add-on for non-BLT owners ( guess we'll have to stay tuned on this . . .perhaps add-on will be lowered at some point as well for owners at other DVCs )
All other
DVC resorts add-on minimum is 25 points; 50 points if you want
Disney's financing.